improvements to Humboldt configuration
- add global event cut
- add more track and vertex selections
- add basic test for SciFi alignment
- add utility function to get XMLWriter list
- add configuration with Velo track refitting (courtesy of @wouter)
- make PVs and particles optional in configuration, fall back to dummy PVs and particles from EmptyProducers
requires Rec!2832 (merged)
Edited by Florian Reiss